Switch mechanism



Aug. 17, 1937. A. M. DRAVING Er A1.

SWITCH MEGHANISM Original Filed Feb. 27, 1931 3 Sheets-Sheet 1 Agg. 17,1937. A. M. DRAVING ET AL 2,090,347

SWITCH MECHANISM y 'original Filed Feb. gv, 1931 5 sheets-sheet 2 llllAug. 17, 1937. A. M. DRM/1N@ ET AL 2,090,347

SWITCH MECHANISM Original Filed Feb. 27,f 1931 3 Sheets-Sheet 3 11 J5 i70 *|17* JOS Il wax au l J 1l @a fa/@@5116 Bral/mg, 97WZZz'amf/aazfga/IZ Patented Aug. 17, 1937 SWITCH MECHANISM Arthur M.Draving and William Irwin Ingham,

Philadelphia, Pa., asslgnors, by mesne assignments, to Chicago TelephoneSupply Company, Elkhart, Ind., a corporation of Indiana Originalapplication February Z7, 1931, Serial No.

518,836. Divided and this application February 4, 1935, Serial No. 4,807

3 Claims.

Our invention relates to electrical switches, either separately or incombination with potentiometers, volume controls, tone controls orresistances, the present application being a division of our copendingapplication, Serial No. 518,836, entitled Electric switch and the like,tiled February 2'7, 1931.A

A purpose of our invention is to throw a switch by means of a trippinglever, preferably pivoted on the switch blade pivot, and to hold theswitch blade in open or closed position by pressure from the movable endof the switch blade against the tripping lever in one of its limitingpositions.

A further purpose is to provide an extension from a tripping lever, sothat the switch may be thrown by engaging the extension.

A further purpose is to shape a tripping lever extension so that aprojection moving over a predetermined path can engage the extension inone position, and, after throwing the switch, move free of theextension.

A further purpose is to limit the movement of a tripping lever and ofits switch blade by stops, preferably using a single stop to engage thetripping lever in both of its extreme positions and to engage the switchblade in open position.

A further purpose is to mount a switch to be operated by apotentiometer, volume control, tone control or resistance dial withinthe control or other casing, and to throw the switch by a projectionfrom the movable contact of the device, preferably insulating theprojection from the contact.

A further purpose is to place within the casing of a potentiometer,volume control, tone control or other variable resistance, a switchoperated by the movable contact, and to open and close the switch in aplane parallel to the plane of movement of the contact.

A further purpose is to trip a full stroke switch by one portion of themovement of a projection from a resistance-varying contact, desirablyhaving the projection move free of the tripping mechanism in otherpositions.

A further purpose is to locate a. switch within the annular space insidea resistance coil and to operate the switch by turning the dial by whichthe resistance is varied.

Further purposes will appear in the specication and in the claims.

In the drawings we illustrate a few only of the numerous variations inwhich our invention might be embodied, choosing the forms shown from thestandpoints of ease in construction,

(Cl. 20o-67) satisfactory operation and convenient illustration of theprinciples involved.

Figure l is a rear elevation of a switch embodying our invention. Y

Figure 2 is a section taken upon the line 2 2 of Figure 1.

Figure 3 is a detached perspective view of the principal parts of theswitch of Figures l and 2.

Figure 4 is a perspective view of a somewhat different form of `ourinvention, in which the switch is located in the same casing as apotentiometer, volume control or tone control and is thrown by movingthe dial.

Figure 5 is a section of the form of Figure 4, taken upon the line 5 5of Figure 6.

Figure 6 is a section upon the line 6 6 of Figure 5.

Figure 7 is a section corresponding to Figure 6, but showing the switchin its opposite position.

Figure 8 is a section upon the line 8 8 of Figure 5.

Figure 9 is a fragmentary section upon the line 9 9 of Figure 8.

Figure 10 shows a variation in a section taken upon the line I0 l0 ofFigure 11.

Figure l1 is a section of Figure l0 upon the line H l I.

Figure l2 is a View corresponding to Figure 1l, showing the switch inits closed position and omitting some of the contacts extending beyondthe casing.

Figure 13 is a section upon the line |3 I3 of Figure l0.

Figure 14 is a. section of Figure 1l upon the line I4 |4.

In the drawings like numerals refer to like parts.

Numerous switches upon the market will operate by motion transmittedthrough turning a shaft, but relatively few switches may be thrown bysubstantially translatory movement of a switch operating projection, andof these, even fewer embody the full stroke feature.

In switches intended for opening and closing electric 1ighting circuits,radio circuits and the like, provided suitable electrical and mechanicalcharacteristics are present, cheapness is the prime essential. Theelimination of a single part or the change of a part so that it may beproduced by a cheaper process, may make it possible to sell a switchwhich could not otherwise be placed upon the market.

We have invented a switch which meets the electrical and mechanicaldemands exceptionally well, and at the same time is extremely simple inconstruction. Aside from the switch blade and its pivot, only threeparts are required in our preferred construction to perform both thetripping and full stroke functions. Oi these, one is a 5 spring and theothers are extremely simplestampings.

Essentially this embodiment of our invention involves the use of atripping lever to throw the switch blade through a toggle of which thetripping lever forms one element.

In the drawings we illustrate our switch separately and also embodied intwo slightly variant forms of volume control. We will rst describe theconstruction of the switch proper, as seen in l5 Figures 1, 2, 3, 5, 6,7, 9, 11,12, and 14.

The switch contacts comprise a stud 2|) and a spring strip 2|, which areconnected together by a switch blade 22 when the switch is in closedposition as seen in Figures 7 and 12. The switch 20 blade 22 is pivotedat 23, and moves to open position as shown in Figures 6 and 1l.

On a pivot line within the edge of the switch blade and preferably onthe switch blade pivot 23 as shown, we place a tripping lever 24, whichis '-5 free to turn with respect to the switch blade 22.

One end of the tripping lever 24 is notched at 25 to engage acooperating notch 26 in a plunger 21.

A recess 28 in the plunger 21 permits the 30 plunger to fit rmly intothe tripping lever `notch 25 without being forced therefrom by theopposite walls of the notch.

The plunger 21 is reduced in width at 29, forming shoulders 38 againstwhich a spring 3| sur- 35 rounding the reduced portion 29 of theplunger, is held. 'Ihe other end of the plunger passes through anopening 32 in atab 33 turned out perpendicularly from the movable end ofthe switch blade 22. The tab 33 holds the spring, while the 40 plungeris free to move through the tab.

The tripping lever 24 is notched at 34, opposite to the notch 25, forengagement of a trippingY projection 35. The edges 36 and 31 of thenotch 34 are preferably not symmetrical, so that the 45 trippingprojection may move out of the notch on one side.

A single stop 38 serves to limit the movement of the tripping lever 24in both open and closed positions and of the switch blade 22 in openposi- 50 tion. When the switch is closed, the shoulder 39 of thetripping lever engages the stop 38 as seen in Figures 7 and 12. In openposition of the switch, the portion 40 of the tripping lever engages thestop, and the portion 4| of the switch 55 blade 22 also engages thestop, but the engagements are upon different portions of the stop asseen in Figures 6 and 11, so that the resultant lateral pressure againstthe stop is not excessive.

The operation of the switch embodies the full- 60 stroke principle.Considering the switch in closed position as shown in Figures 7 and 12,the switch blade 2,2 is resiliently pressed against the switch contacts20 and 2| by the spring 3|. The spring 3| acts at one end against themovable end 65 of the switch blade 22 and at the other end, through theplunger 21, against the tripping lever 24 and ultimately against thestop 38.

It willbe evident that the plunger 21 and the tripping lever 24 form atoggle, from which the 70 switch blade is resiliently pressed intoclosed position.

The switch is shown in open position in Figures 6 and 11.

To open the switch, the tripping lever 24 is 5 moved to its oppositelimiting position in any suitable manner, as by contact of the trippingprojection 35 against the edge 31 of the tripping lever notch 34. Thisswings the toggle to the other side of its neutral position, so that thetripping lever portion 40 engages the stop 38, and the plunger 21 swingsabout the walls of the opening 32 in the switch blade tab 33 as a pivot,while the walls of the notch 26 in the swinging end of the plunger 21maintain their engagement with the walls of the notch 25 in the trippinglever 24.

Shifting of the position of the toggle compresses the spring 3|, so thatas soon as the toggle passes its neutral position, the switch blade issnapped to open position under the action of the spring, simultaneouslywith or even before the arrival of the tripping lever against the stop.The switch blade 22 comes to rest when the portion 4| of the switchblade strikes the stop 38.

The details of the switch housing and of the means for operating thetripping projection are immaterial to the broad aspects of ourinvention. However, certain features of the housing and of the operationof the tripping projection cooperate very desirably with the switch ofour invention, particularly because the plane of movement of the switchblade in opening and closing is the same as the plane of movement of thetripping projection, so that the switch assembly may be made verycompact.

In Figures 1 to 3 we show our switch in a casing intended to hold theswitch alone. The parts of the switch proper, as previously described,are mounted upon a base 42 of insulating material. The stu-d 20 passesthrough the insulation and is riveted to a contact 43 on the back. Theswitch spring contact 2| is secured by a rivet 44 to a contact 45. Fromboth of the contacts, 43 and 45, ears 46 have been bent down andextended through the insulation to prevent turning of the contacts 43and 45. An opening 41 in the spring contact 2| admits the end of an ear46, to prevent the contact 2| from turning.

Openings 46 and notches 49 in the contacts 43 and 45 facilitateattachment of wires to the contacts. The stop 38 is the head of a rivetpassing through the base 42. The switch blade pivot 23 is also desirablya rivet, on which a washer 58 is placed to provide a smooth bearing forthe switch blade.

The switch is enclosed within a casing 5|, flanged outwardly at 52 tohold the insulating switch base and peened at 53 to prevent removal ofthe base.

'Ihe casing is adapted to be supported from a panel by tightening a nutupon a bushing 54 against a lock nut 55. The bushing is reduced indiameter at 56 where it passes through an opening in the casing 5|, andturned over at 51 to unite the bushing to the casing.

Through the interior of the bushing passes a spindle 58 which is coinedat 59 at one end to receive an arm 60, desirably of insulating material,having a triangular opening 6|, and a stop 62 having an opening63. Thearm 68 and the stop 62 are secured to the spindle by riveting the coinedend 59. On the movable end of the arm 66 is secured a switch trippingprojection 35 by riveting at 64 and by extending an ear 65 through thearm 60.

The stop 62 carries a segment 66, which moves between limiting positionsin contact with one or the other of the clips 61 and 68 pressed up fromthe body of the casing. In the form of Figures 1 to 3, the spindle 58performs no other furction than that of throwing the switch. so that bythat name.

In designing radio panels it is highly desirable to have as few knobsand dials as possible. The initial movement of the variable resistancedial commonly carries the contact over an insulating strip before theresistance winding is reached, and therefore is not directly effectivein changing the resistance. It had been proposed to connectV thevariable resistance contact to a switch, desirably the main circuitswitch of the set, so that the switch will be closed by this initialvariable resistance dial movement, and, when turning the variableresistance dial back to its initial position, so that the switch will beopened.

-In this way the extra knob ordinarily necessary for control of a switchis eliminated. The connection in the past has been made from thevariable resistance through a system of levers to a separate switch unitusually supported upon the back of the variable resistance casing.

By our invention we are able to mount the switch within the variableresistance casing proper, where the operating connection between thevariable resistance contact and the switch may consist simply of aprojection from the variable resistance contact. The operatingprojection is made to engage and throw the switch at one position of thecontact and to travel free from the switch in the other positions.

In order to avoid possible short-circuiting of l the switch or thevariable resistance, we insulate we intend the illustration of thevariable resistance shown by us to be essentially diagrammatic, sinceour invention is applicable to any variable resistance having a movingcontact maker, whether the moving body is the resistor or a contactsliding along the resistor.

In Figures 4 to 9. the casing 10, desirably made of metal, is formed intwo parts, consisting oi.' a front 1I and a rear 12 joined by anging at13 and peening at 14.

Within the front part 1i of the casing we show a resistance winding 15upon a form 18 and annularly surrounding an insulating disc 11. Toprevent contact between the resistance winding 15 and the casing, aninsulating sheet 18 covers the inside of the front easing face. I

The movable contact of the variable resistance consists of a springmetal clip 19 supported by annular arms 80 from a central disc 8isecured upon the variable resistance spindle 58'. Cut from the centraldisc, a brush 82 wipes over the face of a disc 83 integral with acontact 84 extending through an insulating sheet 85 covering an opening86 in the casing. I'he disc 83 has an ear 81 turned down and held in anopening 88 in the insulating disc 11. An ear 89 punched up from thecasing front 1| also enters the opening 88. The ears assist in centeringthe respective parts.

Connection is made to the ends of the resistance winding 15 by contacts80 and 9i bent into recesses 92 in the disc 11 and secured by screws 93.Where the winding is used as an ordinary rheostat, the contact 84 andone only of the contacts 90 and 9| will be employed, but where thewinding is used as a potentiometer, the three contacts will all be used.

The construction of the bushing, spindle and stop mechanism issubstantially the same as that shown in Figures 1 to 3, except in a fewfeatures as noted. The narrow portion 58 of the bushing extends throughthe insulating disc 11 and the contact disc 83 and is turned down at 51.A clip 61' is bent up from the contact disc 83 to engage the segment 56of the stop 62 secured to the coined end of the spindle, and limitmovement of the movable contact 19. The single clip 61 engages the stopin both limiting positions.

As seen in Figure 5, the spindle 58' extends through a panel 94 andcarries a dial 95 which covers a nut 36 holding the variable resistanceto the panel.

Thus far we have described what is essentially a conventional variableresistance. On the back casing portion 12 we mount a switch similar tothat shown in Figures 1 to 3. Attachment of the switch base 42 to thecasing is desirably made by rivets 91 as shown.

On the movable variable resistance contact 8| we secure in any suitablemanner as by rivets 88, an insulating piece 98 to the outer end of whichthe tripping projection 35 is fastened. As an additional protectionagainst failure of electrical insulation between the variable resistanceand the switch, we secure an insulating partition |08 to the base of thetripping projection 35.

When the movable contact 19 is in its limiting position at the end ofthe resistance winding connected to the contact 90, as shown in Figure8, the tripping projection 35, opposite to the movable contact 19, is inthe position shown in Figure 6, with the switch open. 'I'he spindle 58',contact 19 and tripping projection 35 cannot travel furthercounter-clockwise (as seen from the iront) because of the spindle stop62 and also because of the switch stop 38.

Movement of the spindle 58' clockwise is however possible, and the rstpart of the clockwise l stroke is eiective to throw the switch from theopen position as shown in Figure 6 to the closed switch position asshown in Figure 7. Further clockwise movement of the spindle 58disengages the tripping projection tripping lever 24. 'Ihe trippingprojection 35 is seen in Figure 7 just after leaving the slot 34.

Further clockwise travel of the spindle 58 carries the movable contact19 over the variable resistance winding 15, varying the resistanceconnected between the respective contacts 90, 84, and 8i in the usualmanner.

Reversal of the direction of turning of the spindle ilrst carries themovable contact 'I8 over the resistance winding 15, and nally causes thetripping projection 35 to engage the tripping lever 24 and open theswitch.

Thus the initial and final ranges of movement of the variable resistanceare employed to close and open a switch, which will ordinarily be themain circuit switch in a radio set.

A In Figures 10 to 14 we illustrate a somewhat different form ofcomposite variable resistance and switch, in which the switch is locatedwithin as from the not a4 of the the annular space inside the variableresistance, thus minimizing the space requirement and permitting closerconnection between the variable resistance spindle and the switch.

The variable resistance in this form is essentially the same as thatillustrated in Figures 4-9 except for variations in detail. The casingis formed in two parts, of which the front portion 1|' is metallic andthe rear portion 12' i0 is molded from suitable insulating material. Thei'ront portion 1|' has been annularly flanged at |0| to fit within anannular depression |02 in the molded rear casing portion 12. At points|03 part of the outer edge of the metal casing 15 portion 1| has beencut away toallow the casing to clear projections |04 extending from thewalls of the depression |02 and to permit the front casing portion 1|'to be held in position by turning it with respect to the rear casingportion The terminal 84' lies on the outside of the front casing portion1 and extends through the terminal notch 842 in the rear casing portion,12'. 'I'he notch 842 prevents turning of the front casing portion 1|'with respect to the rear portion 12', so that the terminal 84' mustbesprung out of the notch 842 before the front casing portion 1|' can beturned with` respect to the rear casing portion 12 to separate thecasing portion. The

terminal 84' is united to the casing portion 1| by turning down the end51 of the bushing 54. A projection 81, punched up from the front casingportion 1|', engages the movable stop 62 as .in the other forms. An ear|05, turned down from the terminal 84', passesthrough the opening in thefront casing portion 1|' formed by punching out the projection 61, toassist in centering the terminal.

The method of attachment of the movable stop 40 62 and of the movablecontact 19 to the spindle 58 is identical with that used in the otherforms. In Figure 13 we illustrate notches |06 in the movable contactdisc to assist in connecting together a plurality of contacts foroperation by a single spindle, where that is desired. 1

The resistance Winding- 15 and the form 16 diier somewhat from thatshown in Figures 4 to 9, as the winding has been made wider to fit intoa depression |01 formed by an annular ridge |08 in the base of themolded casing 12'.\ Connection to the ends of the resistance winding isprovided by contacts 90 and 9|' secured to the winding by screws 93',extending through the casing.

The switch has been mounted on abase 42 secured to the casing by rivets|09, and rested on the inner edge of the ridge |08. Leads ||0 extendfrom the switch contacts 43 and 45' to contacts and ||2 secured to therear of the 00 casing 10' by rivets ||3.

It will of course be evident that the space between the switch base 42and the rear of the casing portion 12' may be used as desired, forexample to hold a fixed resistor.

The structure just described is particularly desirable because spaceradially within variable resistance windings which otherwise would notbe advantageously used, is employed to hold the switch. This is madepossible because the switch opens and closes in a plane parallel to theplane of movement of the movable contact of the variable resistance.

It will be evident, that, besides providing a distinctly useful switch,we provide a switch which is particularly well suited for embodiment ina variable resistance, because it may be thrown by a projection from themovable contact during a tions and modicatlons to meet individual whimor particular need will doubtless become evident to others skilled inthe art, to obtain all or part of the benets of our invention withoutcopying the structure shown, and we, therefore, claim all such in so faras they fall within the reaonable spirit and scope of our invention.

Having thus described our invention, what we claim as new and desire tosecure by Lettersl Patent is:-

1. In a switch assembly, a cylindrical metallic housing, one end wall ofsaid housing being formed of a flat sheet of non-conducting material, apair of switch contacts carried by said end wall, a pivotlcarried by theend wail spaced from the cylindrical housing wall, a switch armsupported by the pivot adjacent the end wall and movable parallelthereto, a switch actuating member carried by the pivot, spring togglemeans connecting the switch arm and actuating member, an extension onsaid actuating member toward the cylindrical housing Wall and away fromthe switch arm, and means for engaging said extension to actuate theswitch to move the switch arm into and out of bridging engagement withsaid contacts.

2. In a switch assembly, a cylindrical metallic housing, one end wall ofsaid housing being formed of a iiat sheet of non-conducting material, apair of switch contacts carried by said end wall, a pivot carried by theend wall spaced from the cylindrical housing wall, a switch armsupported by the pivot adjacent the end wall and movable parallelthereto, a switch actuating member carried by the pivot, spring togglemeans connecting the switch arm and actuating member, a forked extensionon said actuating member toward the cylindrical housing wall and awayfrom the switch arm, and means for transiently engaging said extensionto actuate the switch to move the switch arm into and out of bridgingengagement withv said contacts.

3'. In a switch assembly, a cylindrical metallic housing, one end wallof said housing being formed of a ilat sheet of non-conducting material,a switch contact carried by said end wall, a pivot carried by the endwall spaced from the cylindrical housing wall, a switch armsupported bythe pivot, a switch actuating member carried by the pivot, spring togglemeans connecting the

